Spark-plug



A. T. CRANE. SPARK PLUG APPLICATION FILED FEB. 25. I920.

Patented Feb. 1,1921.,

U ITED STAT-ES PATENT orrlca.

ARTHUR T. CRANE, OF WATERBURY, CONNECTICUT, ASSIGNOR TO THE COMPANIES INC., OF WATERBURY, CONNECTICUT, A CORPORATION.

SPARK-PLUG.

To all whom it may concern:

Be it known that I, ARTHUR T. CRANE a citizen of the United States, reslding at State of Connecticut, have invented 'a new and useful Improvement in Spark-Plugs;

- and I do hereby declare the following, when taken inconnection with the accompanying drawings and the characters of reference marked thereon, to be a full, clear, and exact description of the same and which said drawings constitute part of this application, and represent, in-

Figure 1,. a view in side elevation of a spark-plug embodying m .invention.

F 2, a view in centra longitudinal sec -tion of the shell showing the installation therein ofthe locking-ring, as a condition precedent to the insertion of the insulator .20

or core. 1 t

Fig. 3, a view showing the introduction of the core into the housing after the installa tion'of the locking-ring therein. Fig. 4 a broken sectional view showing the locking-ring as upset for permanently fastening the core in the shell.

Fig. 5, a detached plan view of the lockin -r1ng before swagin ig. 6, a viewthereo in side elevation. Fig. 7, a detached plan view of the seal- 1n gasket.

ig. 8, an edge view thereof. My lnventionrelates to an improvement I in 'spark-plugs, the object being to provide simple and effective meansfor .permanently securing their insulators or cores in their shells.

. described and pointed out in the claims; and

in a method having certain steps as will be hereinafter described.

. In carrying out my invention, as herein shown,l el nploy a shell or housing 2 having an under-cut annular recess 3 formed within its upperedge for the reception of the cross- Specification of Letters Patent.

a-. 'terbury, in thecounty of New Haven and of which Patented Feb. 1, 1921.

Application filed February 25, 1920. Serial No. asi,17e.

sectionally wedge-shaped loweredge of a soft metal locking-ring 4 which is installed in the shell 2 prior to the introduction thereinto of the insulator or core 5, the largest diameter of which adapts it to fit snugly within the shell and also to passthrough the locking ring which is of uniform internal diameter, though its external diameter is enlarged toward its lower edge to. fill the under-cut recess in the shell and'so to adapt the said edge to function as an anchor.

The locking-ring, is first installed in the recess -3 in the shell, as shown in Fig. 2, after which the core is inserted, as shown in Fig. 3. A conical sealing-gasket 6 is then set within the open outer edge'of the ring 4 so as to rest upon the beveled retaining-shoulder 7 of. the core, after which the projecting outer edge of the ring is swaged, spun, or otherwise upset inward over the said' gasket so as to form an angle with its wedge-shaped inner portion, whereby the i sulator or core is permanently held in place within the shell by its engagement at a point without the same.

In other respects than as described, the

spark-plug may be of any approved con-. struction. As erein shown, it is provlded with the usual gas-check gasket 8, a' wire electrode 9, a ground-terminal 10, a termlnal-cap 11, and a binding-nut 12, with none parts is my present invention concerned V The locking-ring 4 maybe produced and installed in a variety of ways. As shown in Figs. 5 and 6, it consists of a tubular blank 13 having its inner edge beveled outwardly .as at 14. Such a blank having been inserted into the shell, is subjected'to pressure operations whereby its beveled lower edge is turned outward into and upset in the undercut-annular locking-recess 3, after which the core 5 is inserted into the shell through the ring. However, I do -not limit myself to making the ring of any particular form, so long as it is adapted in its form to be selfanchored in the shell and to project there-- from so as to' be engaged with the insulator or core at a point outside of the shell. I claim:

1. A spark-plug having a shell formed just within its upper end with'an annular under-cut locking-recess, an insulator or core, and a deformable locking-ring adapted at its inner end to be anchored Within the said in the said shell, the said ring having its in-- ner edge thickened to form an anchor within the said recess and its outer end adapted to be turned inward over the insulator or core ata Point outside of the shell.

3. n a spark-plug, the combination with a shell, formed within its upper edge with an annular under-cut recess, of an insulator or core adapted to be set within the said shell, and a locking-ring having its inner edge en 1 tered into the said recess in which it is upset and anchored and having its outer end engaged with the core or insulator at a point without the shell.

, 4. In a sparklug, the combination with a shell formed ]I1St within its upper end with an annular under-cut locking-recess, of

an insulator or core provided with a retaining-shoulder, a deformable locking-ring having its inner end anchored within the said recess and adapted to be turned inward over the said shoulder at a point without the said shell, and a sealing-gasket ap lied to the said shoulder and interposed tween the same and the projecting outer portion of the ring which is turned down upon it.

5. A method of assembling spark-plu consisting in installing and anchoring a loc ing-ring just within the u per end of a spark-plug shell, then intr ucing an insulator into the shell through the said ring, and finally closing the ring u on a portion of the insulator exposed outsi e of the said shell for holding the insulator in place in the shell.

In testimony whereof, I have signed this specification -1n the presence of two subscribing witnesses.

, ARTHUR T. CRANE.

Witnesses:

JOHN S. Nnaom, JOHN W. HARD. 

